Disclosed herein a seat frame for a vehicle seat, and more particularly, a seat frame for a vehicle seat including side frames arranged on both right and left ends of a seat back frame, and a connection frame for connecting bottom ends of the side frames with each other.
In a seat frame for a vehicle seat, side frames are arranged on both ends of a seat back frame constructing a frame of a seat back, and bottom ends of the side frames are usually connected with each other by a connection frame.
Moreover, among prior-art side frames, there is such a side frame that an upper portion and a lower portion are independent members, and both portions are joined by welding or the like. For this side frame constructed by the two components, the connection frame is provided to connect the members forming the lower portions with each other (for example, refer to Japanese Patent Document No. 2008-201216 A (“the '216 Document”).
On the other hand, when the welding is used to assemble the seat frame, the number of times of welding decreases as the number of the components of the seat frame decreases, which is preferred in terms of workability of the frame assembly. Therefore, in a vehicle seat according to Japanese Patent Document No. 2012-126245 A (“the '245 Document”), each of side frames arranged at right and left sides is constructed by a single member, and the side frames are connected with each other by welding a lower frame, which is the connection frame, to bottom ends of the respective side frames, thereby connecting the side frames with each other.
A description is now given of a frame structure of the vehicle seat according to the '245 Document, and the lower frame is constructed by a metal plate member extending as a straight line, and both ends on an extension direction of the lower frame are welded to rear surface flanges extending from rear surface edges of the side frames toward a seat inside. As a result, the side frames are connected with each other by the lower frame, and a rigidity of each of the side frames, particularly, a rigidity of the bottom end of each of the side frames is secured.
A rigidity of each of the side frames needs to be further increased, and particularly, a rigidity against such a load as to bend the side frame toward the inside of the seat needs to be secured. In other words, if the bottom ends of the side frames are connected by the connection frame to increase the rigidity, the connection frame needs to be attached to secure such a degree of rigidity to suppress the inward bends of the side frames.
Further, when the connection frame is attached to the side frames, the connection frame needs to be attached to further increase the rigidity while interference with members around attached locations are avoided.
Moreover, if the connection frame is attached to the side frames by way of welding, welded areas between the connection frame and the side frames need to be set to promote a welding operation.
Various embodiments of the present invention consider the foregoing problems, and an object of the embodiments is to provide a seat frame for a vehicle seat particularly realizing a structure capable of increasing the rigidity to such a degree as to suppress the inward bends of the side frames in the configuration in which the bottom ends of the side frames are connected by the connection frame.
Moreover, another object is to provide a seat frame for a vehicle seat realizing a structure capable of further increasing the rigidity while the interference with the members around the attached locations are avoided when the connection frame is attached to the side frames.
Moreover, still another purpose is to provide a seat frame for a vehicle seat in which welded areas between the connection frame and the side frames are set to promote the welding operation in the structure in which the connection frame is welded to the side frames.
The above-described problems may be solved by a seat frame for a vehicle seat including side frames arranged on both ends in a widthwise direction of the vehicle seat in a seat back frame provided for a seat back of a vehicle seat, the side frames each comprising a bottom end, and a connection frame for connecting the bottom ends of the side frames, which are attached to a seat cushion of the vehicle seat, with each other, where each of the side frames further includes a side wall arranged outside in the widthwise direction in the side frame, and extending in a top to bottom direction, and a rear wall extending inward from the side wall in the widthwise direction, the connection frame includes first extension portion extending along the widthwise direction, and second extension portions extending forward respectively from both ends in the widthwise direction of the first extension portion, and each of the second extension portions is located inside the side wall in the widthwise direction, and overlaps with the side wall.
When the connection frame is attached to the respective side frames in the seat frame for the vehicle seat, each of the second extension portions, which is a portion of the connection frame, is arranged inside the side wall of the side frame in such a state that each of the second extension portions overlaps with the side wall. This configuration increases the rigidity of the side walls of the side frames, particularly a rigidity against a load acting in the widthwise direction of the vehicle seat, and the inward bends of the side frames are suppressed. In other words, the rigidity can be increased to such a degree as to suppress the inward bends of the side frames in the above-mentioned seat frame for the vehicle seat.
Moreover, the above-mentioned seat frame of the vehicle seat preferably includes a reclining mechanism for swinging the seat back with respect to the seat cushion, where the reclining mechanism is attached to an outside surface located outside in the widthwise direction out of side surfaces of the side wall, the second extension portion abuts against an inside surface located on a rear side of the outside surface in the widthwise direction out of the side surfaces of the side wall, and an area of the side wall of which the second extension portion abuts against the inside surface deviates from an area of which the reclining mechanism is attached to the outside surface.
Welding marks for attaching the reclining mechanism and the like exist on the inside surface of the portion to which the reclining mechanism is attached on the side wall of the side frame, and some recesses and protrusions are thus formed. In the above-mentioned configuration, the connection frame is attached to avoid the portion where the recesses and protrusions are formed by the welding on the inside surface of the side wall of the side frame, and the connection frame can thus be satisfactorily attached.
Moreover, in the above-mentioned seat frame of the vehicle seat, preferably, the area of the side wall of which the reclining mechanism is attached to the outside surface is a circular area viewed in the widthwise direction, and at least a portion of the second extension portion extends in an arc shape along an outer edge of the circular area.
The above-mentioned configuration promotes an operation of attaching the connection frame to avoid the portion to which the reclining mechanism is attached on the side wall of each of the side frames.
Moreover, in the above-mentioned seat frame of the vehicle seat, more preferably, a swing shaft for the swing of the seat back by the reclining mechanism with respect to the seat cushion is provided in such a state as to pass through the side walls in the widthwise direction, and at least a portion of the second extension portion extends in an arc shape to go around from a rear of the swing shaft to a front thereof.
When the connection frame is attached while avoiding the portion to which the reclining mechanism is attached on the side wall of each of the side frames, the above-mentioned configuration enables the attachment of the connection frame to the side walls of the side frames in such a state that the interference with the swing shaft is avoided when the seat back swings with respect to the seat cushion.
Moreover, the connection frame extends in the arc shape to go around from the rear of the swing shaft to the front thereof, and the area in which the portion of the side wall of each of the side frames overlaps with the connection frame is thus somewhat longer in the front to back direction. As a result, the portion increased in the rigidity by the attachment of the connection frame out of the side wall of each of the side frames is provided to extend in the front to back direction of the vehicle seat. As a result, the rigidity of the side frame against the load acting in the widthwise direction of the vehicle seat further increases.
Moreover, in the above-mentioned seat frame of the vehicle seat, further preferably, a side wall side bent portion bending toward the inside in the widthwise direction is formed on a bottom end of the side wall, a second extension portion side bent portion bending toward the inside in the widthwise direction is formed on a bottom end of the second extension portion, and at least a portion of the second extension portion extends so that the second extension portion side bent portion aligns with the side wall side bent portion, and a portion of the second extension portion side bent portion overlaps with the side wall side bent portion.
In the above-mentioned configuration, a unity of the bottom end of the side wall of each of the side frames and the connection frame is enhanced, resulting in a further increase in the rigidity in the bottom end of the side wall of each of the side frames.
Moreover, in the above-mentioned seat frame of the vehicle seat, at least a portion of the area of the side wall of which the second extension portion abuts against the inside surface may be located above the area of which the reclining mechanism is attached to the outside surface, and a bent portion bending toward the inside in the widthwise direction is formed on a top end of the second extension portion.
In the above-mentioned configuration, the connection frame can be attached to avoid the portion to which the reclining mechanism is attached on the side wall of each of the side frames, and the rigidity of the connection frame itself simultaneously increases, which increases the rigidity of the side frames.
Moreover, in the above-mentioned seat frame of the vehicle seat, preferably, the area of the side wall of which the reclining mechanism is attached to the outside surface is a circular area viewed in the widthwise direction, the area of the side wall of which the second extension portion abuts against the inside surface is an area in a C shape along the outer edge of the circular area viewed in the widthwise direction, and the second extension portion includes an upper portion arranged above the circular area and a lower portion arranged below the circular area.
In the above-mentioned configuration, while the portion to which the reclining mechanism is attached on the side wall of each of the side frames is avoided, the connection frame can be attached to the side frames to further increase the rigidity.
Moreover, in the above-mentioned seat frame of the vehicle seat, more preferably, a swing shaft for the swing of the seat back by the reclining mechanism with respect to the seat cushion is provided in such a state as to pass through between the side walls in the widthwise direction, the upper portion and the lower portion are respectively welded to the side wall, a welded area between the upper portion and the side wall extends in a front to back direction of the vehicle seat so that at least a portion of the welded area is located in front of the swing shaft, and a welded area between the lower portion and the side wall extends in the front to back direction so that at least a portion of the welded area is located in the rear of the swing shaft.
In the above-mentioned configuration, the respective upper portion and lower portion of the second extension portion of the connection frame can be satisfactorily fixed to the side wall of each of the side frames. Further, each of the welded areas extends in the front to back direction of the vehicle seat, a strength against a load acting in the front to back direction can be secured, and the state in which the upper portion and the lower portion of the second extension portion are respectively fixed to the side wall of each of the side frames can be stably maintained.
Moreover, in the above-mentioned seat frame of the vehicle seat, a bottom end of the first extension portion at a center may be located further up than the bottom ends of the first extension portion at both ends in the widthwise direction in the connection frame provided for the vehicle seat which is a front seat arranged in front of a rear seat.
The feet of a passenger on the rear seat may enter into a space located below the connection frame of the front seat. If the bottom end at the center in the extension direction is located above the bottom ends of the ends in the extension direction in the first extension portion located above the feet of the passenger out of the connection frame, an interference of the feet of the passenger with the connection frame can be suppressed.
In the seat frame for the vehicle seat according to an embodiment, each of the second extension portions of the connection frame is arranged inside the side wall of the side frame in such a state that the second extension portion overlaps with the side wall, the rigidity of the side frame against the load acting in the widthwise direction of the vehicle seat thus increases, and the inward bend of the side frame is suppressed.
In the seat frame for the vehicle seat according to an embodiment, some recesses and protrusions are formed on the inside surface of the portion to which the reclining mechanism is attached on the side wall of the side frame, and the connection frame can be satisfactorily attached by attaching the connection frame to avoid the portion.
In the seat frame for the vehicle seat according to an embodiment, the operation of attaching the connection frame to avoid the portion to which the reclining mechanism is attached on the side wall of each of the side frames is promoted.
In the seat frame for the vehicle seat according to an embodiment, the connection frame can be attached to the side walls of the side frames in a state in which the interference with the swing shaft is avoided. Further, the portion increased in the rigidity by the attachment of the connection frame out of the side wall of each of the side frames is provided to extend in the front to back direction of the vehicle seat, and as a result, the rigidity of the side frames against the load acting in the widthwise direction of the vehicle seat further increases.
In the seat frame for the vehicle seat according to an embodiment, the unity of the bottom end of the side wall of each of the side frames and the connection frame is enhanced, resulting in a further increase in the rigidity in the bottom end of the side wall of each of the side frames.
In the seat frame for the vehicle seat according to an embodiment, the connection frame can be attached to avoid the portion to which the reclining mechanism is attached on the side wall of each of the side frames, and the rigidity of the connection frame itself simultaneously increases, which increases the rigidity of the side frames.
In the seat frame for the vehicle seat according to an embodiment, while the portion to which the reclining mechanism is attached on the side wall of each of the side frames is avoided, the connection frame can be attached to the side frames to further increase the rigidity.
In the seat frame for the vehicle seat according to an embodiment, the connection frame can be satisfactorily fixed to the side wall of each of the side frames, the strength against the load acting in the front to back direction can be secured, and the state in which the connection frame is fixed to the side wall of each of the side frames can be stably maintained.
In the seat frame for the vehicle seat according to an embodiment, the interference of the feet of the passenger on the rear seat with the connection frame can be suppressed, when the feet of the passenger on the rear seat enter into the space located below the connection frame of the front seat.